The invention discloses a single-phase liquid crystal ammeter capable of avoiding electricity stealing. The single-phase liquid crystal ammeter comprises a meter shell, a live wire and null wire wiring hole for accessing an electric supply, a microprocessor mounted in the meter shell, and a power supply module, a clock module, a storage module, an electric parameter comprehensive detection module, a display module and a commutation module which are connected with the microprocessor. The single-phase liquid crystal ammeter is characterized in that a shielding cover is arranged in the meter shell; the power supply module, the clock module, the storage module, the electric parameter comprehensive detection module and the display module are mounted in the shielding cover; the commutation module is located outside the shielding cover and inside the meter shell; the single-phase liquid crystal ammeter further comprises a self-detection module which comprises a digital control analogue switch connected between a live wire and a null wire in parallel and a testing resistor connected with the digital control analogue switch in series; and a signal end of the digital control analogue switch is connected with the microprocessor. The single-phase liquid crystal ammeter has the advantages of high anti-interference performance, capability of automatically judging electricity stealing or self faults, capability of automatically alarming when abnormal conditions occur, and capability of enhancing the judgment intensity through stress self-detection and initiative self-detection so as to avoid the electricity stealing.